Coupling apparatus for towed underwater vehicle

ABSTRACT

Apparatus for coupling a tow cable to an underwater towed vehicle at a bridle including a shackle connecting the tow cable to the bridle by means of a shear pin and a parallel strain member connected between the shackle and the stern of the underwater vehicle. The strain member is sized to support a towing load higher than the load that causes shearing of the shear pin but less than the load that will break the tow cable. Further means are provided to release the tail fins of the underwater vehicle.

11 1-253. XR; 398050730 SR United States Patent 1191 Henderson et al. I 1 Apr. 23, 1974 [541 COUPLING APPARATUS FOR TOWED 1,160,525 ll/1915 Mustin 1141235 B UNDERWATER VEHICLE 3,560,912 2/1971 Spink 244/3 3,456,901 7/1969 Wieland 244/3 [75] Inventors: Robert F. Henderson, Reading;

0 Connor Houston both PrimaryExaminen-Robert G. Sheridan 0 Assistant Examiner-Gary L. Auton [73] Assignee: E.G.&G. International, Inc., Attorney, Agent, or F irm-.-Ra1ph L. Cadwallader; Leo

, Bedford, Mass. Y M. Kelly {22] Filed: Apr. 9, 1973 211 Appl. No.: 349,167 [571 ABSTRACT igpgratpsjor coupling a tow cableto an underwater,

52 u.s. c1. 114/235 B Vehicle a bridleincluding-15mm?991mm [511 1m. (11.. 860p 7 06 T thitPws b etqib b e s m a Shear pin [58] Field of A 235 F and a parallel strain memberlconnected between the shackle and the stern of the underwater vehicle. Thestrain member is sized to support a towing load higher than the load that causes shearing of the shear pin but less than the load that will break the tow cable. Fur

114/235 R, 217, 207, 208 R; 115/6, 6.1, 7', 244/1 TD, 3, 113, 112; 340/3 T [56] References Citgd 'ther means are rovided to release the tail fins of th UNITED STATES PATENTS underwater while a 3,135,511 6/1964 Norman 244/3 511.788 [/1894 McDonald 114/208 R 3 Claims, 4 Drawing Figures PATENTE APR 23 I974 SHEET 2 BF 2 \Rkllll 1 COUPLING APPARATUS FOR TOWED UNDERWATER VEHICLE The present invention relates to underwater towed vehicles and'in particular to apparatus for recovering the underwater vehicle with the tow cable when the vehicle becomes snagged or caught on an underwater obstruction.

Various projects in oceanographic research and surveying require. that instrumentation be towed behind a vessel at sea at predetermined depths below the surface 'of the ocean. The vehicle housing the instrumentation ususally takes the form of an elongated, substantially tubular body having a bow and tapered stern provided with fins adapted to maintain equilibrium of the vehicle screws, not shown. Shock cord 46 passes around stem 35 of vehicle and through holes 50 in the forward edge of fins 44 where its ends are secured by clamps 48 and 36,. Note that, while clamp 36, secures shock cord 46 to cable 34, clamp 36 is releasably secured to vehicle 10.

' Cable 34 is sized to break at a loading greater than the loading at which pin 28 shears; Also, the loading at which cable 34 will break is less than the loading at which cable 18 will break. Thus, when an obstruction blocks the forward movement (to the left in the drawing) pin 28 shears first, slack 51 in cable 34 is taken up, and cable 16 disconnects from the interior of bridle as illustrated at 52 in FIG. 4. Clamps 36 release cable during underwater travel. A tow cable connects between the vessel and a bridle attached to the vehicle aft of it nose preferably at a point suchthat the line of action of the tow force passes through a point close to that defined by the intersection of the center of gravity and center of drag of the vehicle. The desirability of satisfying this latter condition creates a V-shaped configuration between the vehicle and bridle. All too often underwater obstructions become snagged or caught in the V-shaped configuration resulting in the loss of the underwater vehicle caused by breaking of the tow cable.

Accordingly it is an object of the present invention to provide coupling apparatus for underwater vehicles which reduces or eliminates the risk of loss ofthe vehi- .cie as a result of encountering an underwater obstruction.

Other objects and features of the invention will become apparent upon consideration of the following detailed description which proceeds with reference to the accompanying drawings, wherein:

FIG. 1' illustrates a side elevational view of the underwater vehicle being towed by ,a vessel at sea;

FIG. 2 illustrates a preferred embodiment of the present invention incorporated in operative relationshi with the underwater vehicle;

FIG. 3 illustrates details of a portion of the embodiment of HO. 2; and

FIG. 4 illustrates operation of the coupling apparatus of FIGS. 2 and 3 when the vehicle becomes snagged on an underwater obstruction.

FlG. Lil lugtrates underwater vehicle 10 being towed by a vessel 12 by 'iii'afis 6f is; c able 14. Tow cable 14 includes electrical cable 16 and steel cable 18; Electrical cable 16 connects the instrumentation housed in vehicle 10 to utilization instrumentation carried aboard vessel 12. Methods for assembling cables l6 and 18 to form tow c ab lejfi arje well-k nogin the art and form no part bf the present invention. Cable 16 connects throiighthe interior, not shown, of bridle 20 to the instrumentation housed in the vehicle. This is seen in greater detail in H6. 3. Cable 18 connects by means of cable clamp 22, thimble 23 and bolt 24 to shackle 26. Shear pin 28 secures shackle 26 to bridle 20. Bolt 30 secures parallel cable 34 by means of cable clamp 31 and thimble 32 to shackle 26. Cable 34 then runs down the length of bridle 2G and along the to surface of vehicle 10 toward stern 35 of vehicle 10. As seen in H0. 2 releasable clamps 36 hold parallel cable 34 fixed in the position shown. At stem 35 cable clamp 37, thimble 38 and bolt 40 secure cable 34 to support 42. Fins 44 are releasably secured to vehicle 10 by nylon' 34, and clamp 36, is released. Shock cord 46 stretches. If fins 44 become snagged, the nylon screws, not shown, shear from stern 35. Fins 44 are released and hang from cable 34 by chock shock 46 and clamps 36, and 48.

FIG. 4 illustrates what happens when an obstruction 54 becomes snagged in V 56 between bridle 20 and the main housing of vehicle 10. The subscripts on reference numerals 10, 18 and 34 in FIG. 4 denote the subsequent positions taken by cable 18, cable 34 and vehicle 10 after cable 16 becomes disconnected from the interior of bridle 20. As is apparent, cables 18 and 34 move upward as vessel 12 proceeds to the left, while vehicle 10 swings around the fulcrum defined by ob struction 54.Vehicle 10 can then be towed past obstruction 54. The fact that this event has occured will immediately become apparent to the scientists on board vessel 12 because cable 16 is disconnected from the instrumentation housed in vehicle 10 and thus,-no more data will be recorded aboard vessel 12.

- It will be seen that the object of the invention has been achieved and the advantages ofthe invention are now apparent. Various modifications and changes in the prefered embodiment of the invention as disclosed are contemplated and may be resorted to without departing from the function or scope of the invention as hereinafter defined by the appended claims.

We claim:

1. Apparatusfor couplinga tow cable to an underwatertowed y ehiclewcomprising: a bridle integrally affixed tothe top surface ofthe un- ;d erwater vehicle at the towpoint on the yehic le the other end ofthe strain cable being connected t o theitejgigfihgunderwater vehicle. 2. Apparatus as in claim 1 in whicli'ih underwater vehicle has tail fins and comprising further shear means operative upon snagging of said tail fins .for releasing said tail fins.

3. Apparatus as in claim 2 further comprising electrical cable means associated with the-tow cable and connected to the underwater vechicle and adapted upon shearing of the shear pin to disconnect from the underwater vehicle; 

1. Apparatus for coupling a tow cable to an underwater towed vehicle comprising: a bridle integrally affixed to the top surface of the underwater vehicle at the tow point on the vehicle; a cable clamp and first timble secured to the tow cable; a cable clamp and second thimble secured to one end of a strain cable sized to support a first towing load less than the towing load that will break the tow cable; and a shackle having means whereby the first and second thimbles can be secured thereto with bolts and further means whereby the shackle can be secured to the bridle with a shear pin sized to shear at a second towing load less than the first towing load, the other end of the strain cable being connected to the stern of the underwater vehicle.
 2. Apparatus as in claim 1 in which the underwater vehicle has tail fins and comprising further shear means operative upon snagging of said tail fins for releasing said tail fins.
 3. Apparatus as in claim 2 further comprising electrical cable means associated with the tow cable and connected to the underwater vechicle and adapted upon shearing of the shear pin to disconnect from the underwater vehicle. 